The invention relates to a reversing contactor electric apparatus comprising two electromagnet systems and two power switch systems housed in a common case, which further receives a mechanical locking device preventing simultaneous movement of the mobile armature pieces of these two systems, switches with reciprocal locking being further disposed in the circuits supplying these electromagnets for preventing energization of that one of these two electromagnets which is not concerned.
In such apparatus which are very often used either for feeding multi-phase motors with two directions of operation, or for that of star-delta starters, it is frequently desirable to associate, with the mechanical locking device preventing simultaneous movement of the armatures, an electric locking device preventing simultaneous energization of the coils of the two electromagnets.
Usually, such locking is provided by means of auxiliary switches whose contacts are placed in series with the coils, these switches being either associated externally of the common case or else associated respectively with each of the two adjacent contactors when, for lack of combined apparatus, two separate contactor apparatus must be associated together between which is disposed a mechanical locking device.
However, the fact of using for each contactor, for the purpose of electric locking, one of the switches contained in an auxiliary contact case deprives the user of two switches which could be useful for accomplishing other programs of automatic control and/or signalling, whereas an external wiring operation must be systematically carried out.
The mechanical locking devices frequently comprise two mobile parts, the respective conjugation of the movements of which with those of the armatures give every satisfaction when the relatively narrow manufacturing tolerances are respected, the probabilities of malfunction are however never excluded considering in particular the progressive modifications of their dimensions during large-scale manufacture, which must further accommodate inevitable wear attributable to their operation.
The recent developments in the field concerned result from the needs felt by numerous users of multi-phase motors of having apparatus which are simple to mount and connect, even if it entails a complete replacement when only one of the two contactors is damaged.